// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_SSL_CHANNEL_ID_STORE_H_
#define NET_SSL_CHANNEL_ID_STORE_H_

#include <list>
#include <memory>
#include <string>

#include "base/callback.h"
#include "base/threading/non_thread_safe.h"
#include "base/time/time.h"
#include "crypto/ec_private_key.h"
#include "net/base/net_export.h"

namespace net {

// An interface for storing and retrieving channel ID keypairs.
// See https://tools.ietf.org/html/draft-balfanz-tls-channelid-01

// Owned only by a single ChannelIDService object, which is responsible
// for deleting it.
class NET_EXPORT ChannelIDStore
    : NON_EXPORTED_BASE(public base::NonThreadSafe) {
public:
    // The ChannelID class contains a keypair, along with the corresponding
    // hostname (server identifier) and creation time.
    class NET_EXPORT ChannelID {
    public:
        ChannelID();
        ChannelID(const std::string& server_identifier,
            base::Time creation_time,
            std::unique_ptr<crypto::ECPrivateKey> key);
        ChannelID(const ChannelID& other);
        ChannelID& operator=(const ChannelID& other);
        ~ChannelID();

        // Server identifier.
        const std::string& server_identifier() const { return server_identifier_; }
        // The time the keypair was created.
        base::Time creation_time() const { return creation_time_; }
        // Returns the keypair for the channel ID. This pointer is only valid for
        // the lifetime of the ChannelID object - the ECPrivateKey object remains
        // owned by the ChannelID object; no ownership is transferred.
        crypto::ECPrivateKey* key() const { return key_.get(); }

    private:
        std::string server_identifier_;
        base::Time creation_time_;
        std::unique_ptr<crypto::ECPrivateKey> key_;
    };

    typedef std::list<ChannelID> ChannelIDList;

    typedef base::Callback<
        void(int, const std::string&, std::unique_ptr<crypto::ECPrivateKey>)>
        GetChannelIDCallback;
    typedef base::Callback<void(const ChannelIDList&)> GetChannelIDListCallback;

    virtual ~ChannelIDStore() { }

    // GetChannelID may return the result synchronously through the
    // output parameters, in which case it will return either OK if a keypair is
    // found in the store, or ERR_FILE_NOT_FOUND if none is found.  If the
    // result cannot be returned synchronously, GetChannelID will
    // return ERR_IO_PENDING and the callback will be called with the result
    // asynchronously.
    virtual int GetChannelID(const std::string& server_identifier,
        std::unique_ptr<crypto::ECPrivateKey>* key_result,
        const GetChannelIDCallback& callback)
        = 0;

    // Adds the keypair for a hostname to the store.
    virtual void SetChannelID(std::unique_ptr<ChannelID> channel_id) = 0;

    // Removes a keypair from the store.
    virtual void DeleteChannelID(
        const std::string& server_identifier,
        const base::Closure& completion_callback)
        = 0;

    // Deletes the channel ID keypairs that have a creation_date greater than
    // or equal to |delete_begin| and less than |delete_end| and whose server
    // identifier matches the |domain_predicate|. If base::Time value is_null,
    // that side of the comparison is unbounded.
    virtual void DeleteForDomainsCreatedBetween(
        const base::Callback<bool(const std::string&)>& domain_predicate,
        base::Time delete_begin,
        base::Time delete_end,
        const base::Closure& completion_callback)
        = 0;

    // Removes all channel ID keypairs from the store.
    virtual void DeleteAll(const base::Closure& completion_callback) = 0;

    // Returns all channel ID keypairs.
    virtual void GetAllChannelIDs(const GetChannelIDListCallback& callback) = 0;

    // Helper function that adds all keypairs from |list| into this instance.
    void InitializeFrom(const ChannelIDList& list);

    // Returns the number of keypairs in the store.  May return 0 if the backing
    // store is not loaded yet.
    // Public only for unit testing.
    virtual int GetChannelIDCount() = 0;

    // When invoked, instructs the store to keep session related data on
    // destruction.
    virtual void SetForceKeepSessionState() = 0;

    // Returns true if this ChannelIDStore is ephemeral, and false if it is
    // persistent.
    virtual bool IsEphemeral() = 0;
};

} // namespace net

#endif // NET_SSL_CHANNEL_ID_STORE_H_
